Choosing the right non-volatile memory is a critical decision in the design of Internet of Things (IoT) devices. Two popular choices—SPI NAND Flash and NOR Flash—often compete for the same design space.
Each has unique strengths, and understanding their trade-offs can help engineers optimize for cost, performance, footprint, and reliability.
1. Architecture Overview
| Feature | NOR Flash | SPI NAND Flash |
|---|---|---|
| Storage Cell | Random access (bit addressable) | Page/block access (sequential) |
| Read Speed | Fast random read | Fast sequential read |
| Write Speed | Slower writes | Faster writes (page-level) |
| Density | Typically ≤512Mb | 1Gb – 8Gb and above |
| Cost per Bit | Higher | Lower |
| Footprint | Larger for high density | Smaller form factor |
2. When to Choose NOR Flash
✅ Firmware Code Execution (XIP)
NOR is ideal for executing code directly from flash (eXecute In Place). No need to copy to RAM.
✅ Ultra-low power
Perfect for battery-powered microcontrollers with sleep-wake cycles.
✅ Small Code Base (<16MB)
Great for bootloaders, BIOS/UEFI, or simple firmware systems.
✅ Simple MCU interfaces
Works with low-end MCUs using Quad SPI or standard SPI.
3. When SPI NAND is the Better Fit
✅ High Capacity Needs (1GB or more)
SPI NAND offers much higher densities at a lower cost per bit than NOR.
✅ Data Logging & OTA Updates
More efficient for storing large files, sensor data, and over-the-air firmware updates.
✅ Compact IoT Edge Devices
Its small package and efficient interface make it great for space-limited PCBs.
✅ Cost-sensitive applications
SPI NAND delivers a better $/MB ratio, ideal for smart home, wearable, and industrial IoT products.
4. Performance & Reliability Comparison
| Factor | NOR Flash | SPI NAND Flash |
|---|---|---|
| Read Latency | Very low | Slightly higher (page read) |
| Write Endurance | Up to 100k P/E cycles | Typically 3K–10K P/E cycles |
| ECC Required | Not usually | ECC required (built-in or host) |
| Boot Reliability | Excellent | Requires bootloader/driver |
| File System Support | Limited (due to small size) | Better with NAND-friendly FS (YAFFS, UBIFS) |
5. Case Use Examples
| Use Case | Recommended Flash |
|---|---|
| Smart light switch | NOR Flash |
| Wi-Fi router with Linux OS | SPI NAND Flash |
| Wearable fitness tracker | NOR or SPI NAND (depends on FW size) |
| Edge AI camera device | SPI NAND Flash |
| BLE beacon | NOR Flash |
| Industrial controller | SPI NAND Flash (Industrial-grade) |
6. UMT’s Flash Solutions for IoT
SPI NAND Flash Lineup:
Densities: 1Gb – 8Gb
Uniform erase block: 128KB
Built-in ECC and bad block management
Industrial-grade options available (–40°C to 85°C)
NOR Flash (Coming Soon):
Low-power, secure boot ready
Ideal for MCUs and firmware execution
UMT, via Pionix Vietnam, supports IoT developers with samples, firmware support, and long-term availability.
Conclusion
There is no one-size-fits-all solution when it comes to embedded flash memory. While NOR Flash shines in low-power, code-execution scenarios, SPI NAND is clearly superior when data storage and cost efficiency are the priority.
Choosing the right flash type depends on your firmware size, boot method, performance needs, and system longevity.
👉 Need help deciding between SPI NAND and NOR Flash?
Reach out to Pionix Vietnam for expert guidance and sample requests.
